A tattoo machine having a body adapted to receive a return spring. The body of the tattoo machine defines a channel which is configured to selectively receive the return spring. The channel is defined through a bottom surface of the tattoo machine body and may be closed on the bottom surface by a cap or retaining means. The return spring may be inserted, removed or replaced without disassembling the body, motor and slide components of the machine. The tattoo machine may be configured or adapted for use with traditional tattoo tubes and needles, or for use with tube and needle cartridges having an internal membrane or bias element acting on the needle.